/* * arch/sh/kernel/cpufreq.c * * cpufreq driver for the SuperH processors. * * Copyright (C) 2002, 2003 Paul Mundt * Copyright (C) 2002 M. R. Brown * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */#include <linux/types.h>#include <linux/cpufreq.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/init.h>#include <linux/delay.h>#include <linux/smp.h>#include <asm/processor.h>#include <asm/watchdog.h>#include <asm/freq.h>#include <asm/io.h>/* * For SuperH, each policy change requires that we change the IFC, BFC, and * PFC at the same time.  Here we define sane values that won't trash the * system. * * Note the max set is computed at runtime, we use the divisors that we booted * with to setup our maximum operating frequencies. */struct clock_set {	unsigned int ifc;	unsigned int bfc;	unsigned int pfc;} clock_sets[] = {#if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH2)	{ 0, 0, 0 },	/* not implemented yet */#elif defined(CONFIG_CPU_SH4)	{ 4, 8, 8 },	/* min - IFC: 1/4, BFC: 1/8, PFC: 1/8 */	{ 1, 2, 2 },	/* max - IFC: 1, BFC: 1/2, PFC: 1/2 */#endif};#define NR_CLOCK_SETS	(sizeof(clock_sets) / sizeof(struct clock_set))#define MIN_CLOCK_SET	0#define MAX_CLOCK_SET	(NR_CLOCK_SETS - 1)/* * For the time being, we only support two frequencies, which in turn are * aimed at the POWERSAVE and PERFORMANCE policies, which in turn are derived * directly from the respective min/max clock sets. Technically we could * support a wider range of frequencies, but these vary far too much for each * CPU subtype (and we'd have to construct a frequency table for each subtype). * * Maybe something to implement in the future.. */#define SH_FREQ_MAX	0#define SH_FREQ_MIN	1static struct cpufreq_frequency_table sh_freqs[] = {	{ SH_FREQ_MAX,	0 },	{ SH_FREQ_MIN,	0 },	{ 0,		CPUFREQ_TABLE_END },};static void sh_cpufreq_update_clocks(unsigned int set){	current_cpu_data.cpu_clock = current_cpu_data.master_clock / clock_sets[set].ifc;	current_cpu_data.bus_clock = current_cpu_data.master_clock / clock_sets[set].bfc;	current_cpu_data.module_clock = current_cpu_data.master_clock / clock_sets[set].pfc;	current_cpu_data.loops_per_jiffy = loops_per_jiffy;}/* XXX: This needs to be split out per CPU and CPU subtype. *//* * Here we notify other drivers of the proposed change and the final change. */static int sh_cpufreq_setstate(unsigned int cpu, unsigned int set){	unsigned short frqcr = ctrl_inw(FRQCR);	unsigned long cpus_allowed;	struct cpufreq_freqs freqs;	int allowable_cpu_map;	if (!cpu_online(cpu))		return -ENODEV;	cpus_allowed = current->cpus_allowed;	allowable_cpu_map = 1 << cpu;	set_cpus_allowed(current, allowable_cpu_map);		BUG_ON(!(allowable_cpu_map & (1 << smp_processor_id())));	freqs.cpu = cpu;	freqs.old = current_cpu_data.cpu_clock / 1000;	freqs.new = (current_cpu_data.master_clock / clock_sets[set].ifc) / 1000;	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);#if defined(CONFIG_CPU_SH3)	frqcr |= (newstate & 0x4000) << 14;	frqcr |= (newstate & 0x000c) <<  2;#elif defined(CONFIG_CPU_SH4)	/*	 * FRQCR.PLL2EN is 1, we need to allow the PLL to stabilize by	 * initializing the WDT.	 */	if (frqcr & (1 << 9)) {		__u8 csr;		/*		 * Set the overflow period to the highest available,		 * in this case a 1/4096 division ratio yields a 5.25ms		 * overflow period. See asm-sh/watchdog.h for more		 * information and a range of other divisors.		 */		csr = sh_wdt_read_csr();		csr |= WTCSR_CKS_4096;		sh_wdt_write_csr(csr);		sh_wdt_write_cnt(0);	}	frqcr &= 0x0e00;	/* Clear ifc, bfc, pfc */	frqcr |= get_ifc_value(clock_sets[set].ifc) << 6;	frqcr |= get_bfc_value(clock_sets[set].bfc) << 3;	frqcr |= get_pfc_value(clock_sets[set].pfc);#endif	ctrl_outw(frqcr, FRQCR);	sh_cpufreq_update_clocks(set);	set_cpus_allowed(current, cpus_allowed);	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);		return 0;}static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy){	unsigned int min_freq, max_freq;	unsigned int ifc, bfc, pfc;	if (!cpu_online(policy->cpu))		return -ENODEV;	/* Update our maximum clock set */	get_current_frequency_divisors(&ifc, &bfc, &pfc);	clock_sets[MAX_CLOCK_SET].ifc = ifc;	clock_sets[MAX_CLOCK_SET].bfc = bfc;	clock_sets[MAX_CLOCK_SET].pfc = pfc;	/* Convert from Hz to kHz */	max_freq = current_cpu_data.cpu_clock / 1000;	min_freq = (current_cpu_data.master_clock / clock_sets[MIN_CLOCK_SET].ifc) / 1000;		sh_freqs[SH_FREQ_MAX].frequency = max_freq;	sh_freqs[SH_FREQ_MIN].frequency = min_freq;	/* cpuinfo and default policy values */	policy->governor                   = CPUFREQ_DEFAULT_GOVERNOR;	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;	policy->cur                        = max_freq;	return cpufreq_frequency_table_cpuinfo(policy, &sh_freqs[0]);}static int sh_cpufreq_verify(struct cpufreq_policy *policy){	return cpufreq_frequency_table_verify(policy, &sh_freqs[0]);}static int sh_cpufreq_target(struct cpufreq_policy *policy,			     unsigned int target_freq,			     unsigned int relation){	unsigned int set, idx = 0;	if (cpufreq_frequency_table_target(policy, &sh_freqs[0], target_freq, relation, &idx))		return -EINVAL;	set = (idx == SH_FREQ_MIN) ? MIN_CLOCK_SET : MAX_CLOCK_SET;	sh_cpufreq_setstate(policy->cpu, set);	return 0;}static struct cpufreq_driver sh_cpufreq_driver = {	.owner		= THIS_MODULE,	.name		= "SH cpufreq",	.init		= sh_cpufreq_cpu_init,	.verify		= sh_cpufreq_verify,	.target		= sh_cpufreq_target,};static int __init sh_cpufreq_init(void){	if (!current_cpu_data.cpu_clock)		return -EINVAL;	if (cpufreq_register_driver(&sh_cpufreq_driver))		return -EINVAL;	return 0;}static void __exit sh_cpufreq_exit(void){	cpufreq_unregister_driver(&sh_cpufreq_driver);}module_init(sh_cpufreq_init);module_exit(sh_cpufreq_exit);MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");MODULE_DESCRIPTION("cpufreq driver for SuperH");MODULE_LICENSE("GPL");